“I have a teenage daughter with heart and kidney failure,” says Jo from Wolverhampton. “Regardless of the great care she receives, her condition can and does suddenly become critical. Her mother lives in constant fear of changes to the NHS and her support system. We must keep a tight hold on our very precious NHS.”

The story of Jo’s family is moving. But it’s not that surprising – most of us have some experience of the NHS as a true life-saver. And sadly, many of us will also recognise the anxiety Jo describes about the future of the NHS.

Elizabeth, from north-west London, has a rare autoimmune disease that requires regular visits to hospital, including overnight stays. She echoes Jo’s fears. “It is imperative that numbers of beds are not cut,” she says, “my last wait for a bed, following complications with an outpatient procedure, was approximately seven hours.” Valerie from Dorset gave 33 years of her career to the NHS as a registered nurse. “Now I am possibly facing cardiac surgery,” she says, “and I need the NHS to support me.”

Many of us have gradually started to feel less confident than our parents and grandparents were that we will be able to rely on the NHS into our old age – let alone that our children or grandchildren will have a service they can trust.

Not all the pressures on today’s NHS are the fault of politicians. We’re living longer. There are more of us. Demand has risen in hospitals and in health centres. But at the same time, government funding for the health service has been dangerously squeezed. Social care is continually neglected, putting even more pressure on hospitals. And successive ministers have refused to listen to doctors, nurses or patients when pushing through politically motivated NHS reorganisations.

Conventional politics has failed us when it comes to the NHS. The voice of ordinary people – the likes of Jo, Elizabeth and Valerie – has never been more needed. And that’s why they and hundreds of thousands of us are taking matters into our own hands. Think back to David Cameron’s costly and damaging NHS reorganisation. Without a people-powered campaign to prevent the worst elements of Cameron’s legislation, the Health and Social Care Act would have had far more harmful consequences.

A new investigation commissioned by the campaign organisation 38 Degrees, where I work as executive director, is published today. Carried out by a team of health policy experts at Incisive Health, it exposes new plans being drawn up for the NHS across England, called “sustainability and transformation plans” (STPs). The investigation has been funded by hundreds of thousands of people making individual donations via the 38 Degrees website. People like Jo, Elizabeth and Valerie have shared their personal stories, signed the campaign petition and donated to fund the research. Independent of party politics, we’ve chipped in to protect the health service we value so much by putting these plans under the spotlight.

The research finds huge funding gaps for local services, which, the experts say, could lead to A&E closures, cuts to beds and mergers of hospitals. Put together, the projected funding shortfalls across England would see a £23bn deficit in health and social care spending by 2021.

Where Jo lives, in the Black Country, there are plans for major changes at Midland Metropolitan hospital, including the closure of A&E. The plans also include the proposal to shut one of two district general hospitals. By 2021, the health and social care system in the Black Country is projected to be £476.6m short of the funds it needs to balance its books while maintaining the same level of care. Where Elizabeth lives, the draft plan indicates “reducing demand for acute services by approximately 500 beds”. That’s health manager-speak for cutting 500 hospital beds.

Our crowdfunded investigation shows that this worrying plan for the Black Country is typical of many others across England.

These kinds of cuts aren’t the fault of local NHS leaders. They’re being planned all across the country, the result of a growing black hole in the funding provided to the NHS by the government. Whether or not Theresa May allows these cuts to go ahead will be a key test of her commitment to protecting the NHS.

The NHS belongs to all of us. So before these plans go any further, local people should have a say on any changes to their services. That’s why almost 250,000 people have already signed the 38 Degrees campaign petition to the health secretary, Jeremy Hunt, calling for full public disclosure of the STPs for each and every one of the 44 areas across England.

No one is suggesting that all changes to NHS services are bad. There may be a good case for some of the changes that are being proposed. But because the plans are not out in the open – we have had to hire specialist researchers to give us even a partial picture – there’s every reason to fear that many of these will be about cost cutting at the expense of patient care and patient safety.

One thing is certain: we know that when we leave the politics of the NHS to the politicians, it doesn’t end well. Now, more than ever, people-powered campaigning is critical to the future of the NHS.